[c131fr]

I was about to purchase a 4 axis kit from ebay, but came here for advice and found the kit was not satisfactory. Then I came across a break out board I had in my giant pile of stuff, and remembered that I once purchased a kit about 7 years ago for an Enco Mill/Drill I had. Just after receiving the kit I got a job overseas, and I pretty much forgot about it. My father sold the mill/drill while I was away, and the cnc kit ended up in a box on a shelf in the corner of a long lost cabinet.

Today, I found the box, and I'm cautiously optomistic. What I found was the following:

4X Clifton Precision JOH-2250-BX-1C motors
4X Geckodrive G320 DC ServoDrives
1 Giant toroidal transformer (no infomation or markings)
1 Giant Capacitor (1/2 size of pepsi can)
varous wires and switches

Earlier, I found a CNC 4 output breakout board that is apparently for this kit.

Everything is new and still in it's box, and in new condtion. The motors look different than what I've been seeing (I suppose because they are servos), with large positive and negative termanals on each side of the motor, and a five pin connector on the bottom labled:

1 GND; 2 Index; 3 Ch. A; 4 +5V; 5 Ch. B


So, is this a good find? I already know the breakout board is no longer made. Not sure about the rest. The motors don't have a flanged mount, only tiny holes for screws. No way they would be strong enough to support the motors.

Anyway, as I mentioned in my other post, I want to build a gantry type CNC mill that is X: 2' Y:3' Z: 1' with a future rotary table. I'm hoping this kit will get the job done. If anyone knows anything about this stuff, I sure would appreciate a response. Thank you.

[c131fr]

The part at the bottom with the 5 pins is a US Digital E2 encoder. Just found the sticker.

[Bubba]

You have the makings of an excellent setup! Those Clifton motors were highly sought after in their day and the Gecko 320 is still being made. As you have the motors, I would "assume" the high output voltage is correct for those motors and will also provide at least a 5V ouput also. You will also need a bridge rectifyer(s) to convert the AC output of the transformer to DC and the big Capacitor is to smooth out the ripple current on the DC side. If you have a name on the breakout board and don't have the schematic, I am sure someone here will be able to help you. The encoder outputs from the servo go to the equivalent points on the Gecko (you will not need or use the "index" .
OH and the screws on the end of the servo will support it!

[c131fr]

Excellent. I found a small Rectron Rectifier in the box. Doesn't look like it does anything. It's just a square with 4 blade terminals on top of it. I hope I can figure out how to build this. Thanks for your reply!

[Bubba]

the rectifier should have a pair of symbols indicating AC (or ~) and the opposing pair + and -
You feed the two leads from the transformer to the AC connections and the +DC to the +side of the cap. The -DC goes to the -side of the cap.

NOTE: once you power up the system, the cap can and WILL hold a charge that will bite you if you get across the terminals for a long period of time. Read up on "linear power supplies"

[bobsch]

Excellent. I found a small Rectron Rectifier in the box. Doesn't look like it does anything. It's just a square with 4 blade terminals on top of it. I hope I can figure out how to build this. Thanks for your reply!

It's probably a bridge rectifier. Two of the terminals will be marked "AC" or "~". They connect to the transformer. the other two are the + and - DC output. The capacitor is connected after the rectifier. Make sure you watch the polarity on the cap. They tend to explode if wired backwards. DAHIKT!!

[c131fr]

Thanks for all your help fellas. I unwrapped all the parts to get a better look at them. The toroidal transformer appears to have two transformers in one. There are two pairs of 120VAC wires and two pairs of 25VAC wires. It's rated at 624 VA and 12.5 amps per wire pair. The rectifier is about 1 inch square, with two parallel terminals with one side labled "AC", and two terminals which are adjacent to one another, one labeled "+" and the other unlabled. I'll just use the multimeter to make sure the polarity is correct. This is looking simpler and simpler every minute, which is a huge red flag for me... I found the vendor of the kit, but he hasn't updated his website in 7 years, and so far no response from email. My kit is the one shown on the bottom of the page here.

[bobsch]

The toroidal transformer appears to have two transformers in one. There are two pairs of 120VAC wires and two pairs of 25VAC wires. It's rated at 624 VA and 12.5 amps per wire pair.

Two secondary windings give you several choices. You can use one and just insulate the unused wires. Or use both. Wire them in series for double the voltage at 12.5 amps, or in parallel for 25 volts and 25 amps.

If you use both windings be very careful when you connect them. if one winding is reverse of the other, a series connection will give you zero voltage. Reversing one in parallel will give you a short circuit and a VERY hot transformer—for a short time. Exciting, but not very useful.

Since the G320 is rated for up to 80 volts, a parallel connection is probably what you'll want to use, assuming the cap is rated for at least that voltage.

[c131fr]

Hello guys. The person who sold me the kit (in 2004, it turns out), sent me the instructions for building the servo controller. It's pretty easy and straight forward, but I decided to test it as I go. So, first I wired the power cord connector to a terminal strip and made sure I had 120VAC. Check. Then I wired the power switch to the terminal board. Check. 120VAC ON, 0VAC OFF.

Then I had a problem. I wired the transformer per the instruction: There's two pairs of high side wires, and 2 pairs of low side. I wired the two high side hot wires to the terminal strip that has the hot side from the wall outlet. I wired the two high side neutral (??) wires together on the neutral side of the terminal strip. The writing on the toroid says 120V (hot) and 0V (neutral). My teminology might be wrong. The instructions say that I will get 25V, 25amp service on the low side wiring it like this, if I pair the low side wires together on their terminal strip.

The first time I plugged it in with the transformer wired, I had the low side pairs wired to the rectifier- and the house breaker popped. I unplugged it and reset the 15amp house breaker. I then looked at the wiring, and couldn't see anything wrong, but just in case I removed the wires and redid everything very slowly and carefully to make sure it's as the instructions say. It is. I disconnected the low side from the rectifier, and plugged the power back in to the wall outlet. It worked! But my stupid multimeter was stuck in DC mode, and I couldn't find the instructions on how to get it out of AUTO for about 10 minutes. When I finally got it in AC mode, I checked that there was 120VAC from the wall- there was. But when I was about to check the voltage at the low side of the transformer, the breaker tripped again.

Now, I had my computer on and an old 32" tube television, but there was no load on the transformer, so I can't see how I pulled more than 15 amps. The transformer will deliver 25 amps under load, but do you think it would pull 10 or 12 amps just sitting there? I was going to try to test it again with the computer off and television off, but I thought I might ask here first rather than catch my wall on fire if the breaker suddenly desides to stick.

Thanks!

[c131fr]

Just to be clear, here is the photo of the lable on the transformer.

I have it wired like this:
High Side:
Gray and Brown to 120VAC (black)
Blue and Violet to 0VAC (white)


Low side:
Red and Yellow to one side of rectifier
Black and Orange to other side of rectifier


That should give me 25 VDC, 25 amp supply coming out of the rectifier.


Oh, and the transformer is wired in parallel instead of series because the instructions say that this is a 25VDC servo motor.

[p38nut]

Did you install the bleed resistor as shown on the schematic? The cap may have been completely discharged and could act as a direct short across power leads. This resistor also helps slow down the current draw to first charge the cap.

[Bubba]

You stated earlier that you got this kit several years ago and as stated above, the cap is probably acting like a direct short right now. Temporarily, put a resistor IN SERIES with one of the leads to limit the current and to "reform" the cap. Something on the order of ~25 to 100 ohm will do for now. It does not have to be precise or exact. You just want to limit the current for now.

[c131fr]

I don't have the cap connected yet. But yes, I have the resistor installed. The wiring stops just after the transformer for now.

Attached is a photo. Note that the top wires coming from the wall are colored backwards. The white wire is hot, the black wire is not. If you can read my bad writing, the white wire is delivering 120VAC, and the black wire isn't. lol

[c131fr]

The low side of the transformer will have wires coming out of that terminal strip going to the rectifier (they are not installed yet), then from the rectifier to the big capacitor. Then on to the servo controllers.

[c131fr]

There is one thing I did different than the instructions. See the attached schematic.

In the drawing, it shows two white wires coming from the plug. I ran just one white wire to the terminal strip, and then one white wire from the terminal strip to the switch. I don't see what the difference would be, but maybe I'm wrong.

So if you were to complete this, I have one white wire coming from the wall plug to the top two terminals (white), which are then connected to the power switch and the transformer high side 0V wires. Is this the problem? If so, why? Thanks!

[Bubba]

The white wire going to the switch is to make the light on the switch light up.

If you don't have the light, that wire can be ignored. You want to switch across the two black wires only!

[c131fr]

Right. And it does.

I read about checking the transformer, so I did that. According to a poster, there should be continuity between the high side leads themselves, and the low side leads themselves, but not from high to low. Test passed. But now I notice that the terminal strip shown in the diagram above rings out across everything. I assume this is because it's AC, and AC kinda just wiggles back and forth, but why isn't that a short? I hate AC... lol Maybe I'll plug it back in and try to read how many amps it is drawing with nothing connected to it...

[c131fr]

Ok, it works. Apparently the way I had the white wire going to the switch for the light from the terminal strip was the problem. I disconnected it and everthing worked fine. The torroid kind of startled me because it made that "transformer sound". After it was on, I got approx. 27 VAC on the low side. Then I accidentally touched the wrong terminal and popped the fuse in my multimeter. Had I decided to be a surgeon, there'd be a bunch of dead people out there...

So now I'm going to wire up the rest of it. I'm scared of the giant cap in there. I've been bit by a much smaller one when I fixed my TV and it hurt like hell, so I'm hoping I don't kill myself with this beast. If I have problems, do I just wait a couple hours before touching it, or is there a safe way to discharge it?

[Bubba]

AS previously stated, a bleed resistor (say 2K ohm 1/2 watt) ACROSS the cap will depending on size discharge is rather quickly. Just remember the smaller the resistor, the larger the current and this translates into wattage size needed. If your in a big hurry (or to double check), I have used a WELL insulated screwdriver across the cap to make sure it is discharged. Just BE CAREFUL

[c131fr]

Ok, thanks. I have a big 1k 5 watt resistor installed now.